Roasting-furnace.



M. VAN M. DE LUMMEN.

ROASTING FURNACE.

APPLICATION FILED mm: 11, 1912.

, O67,045. Patented July 8, 1913.

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ROASTING FURNACE.

APPLICATION I'ILED mm. 11, 1912.

2 SHEETS-SHEET 2.

1,067,045, Patented July 8, 1913.

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ROASTING-FURNACE.

To all whom it may concern.

lie it known that; I, Mainn'cu VAN hilanoun nn LUMMEN, subject of the King of Belgium, residing at Cologne-on-the-Ilthine, Germany, have invented new and useful improvements in ltoasting-l urilaces, of which the following is a specification.

This invention relates to roasting furnaces and more particularly to tier furnaces for the roasting of pyrites and other sulfur compounds. In furnaces of this kind various devices have been proposed for counteracting the production of dust. These devices however only inclliciently fultil recpiiretnents and in practice have proved to be more or less useless. It has for instance been attempted to counteract the production of dust by the provision on the agitating arms of screens rotating with the arms so as to close the drop openings against the hot gas current, or the ore is caused to pass through closed hoppers or along open inclined surfaces. According to another method the ore and the heating gases were caused to pass through separate vertical passages. The use of the rotary screens referred to is practically impossible owing to frictional di'll'icultics caused by the necessary tight closure of the tiers or stages. Moreover in order to prevent the p rodl'lction of dust at relatively great length of screen is required whereby the traveling velocity of the heating gases and consequently the danger of dust being produced are increased. The passage of the material through closed oblique hoppers or through vertical tubes has the drawback that such passages are liable to be readily clogged by ore adhering to their sides, thereby causing the following ore to seek a different path and thus giving rise to the production of dust. Moreover such hoppers or passages cannot be readily cl aned during working.

Now the present invention relates to a screen arrangement for mechanical roasting furnaces, whereby all the drawbacks above mentioned are readily removed.

The characteristic feature of the invention consists in the provision beneath each drop opening, formed with a downward incline in known manner, of an open guide or plate having the same angular inclination and being attached by mains of an arm to the rotary shaft or spindle of the agitating device. This guide extends close to the next lower tier and enables the ore to pass readily Specification of Letters Patent.

Application filed June 11, 1912.

-Patented J uly 8, 1913.

Serial No. 702,951.

and without the production of dust into the lower tier. At the same time the guide protects the downwardly traveling layer from being directly attacked and penetrated by the up\\'ardly passing hot gas current in the furnace.

The upper edge of the guide or screen which is secured to the hollow shaft of the agitating device is caused to rotate in an an nular member or ring which is protected against the adhesion ol the ore and which moreover prevents the gas current; from striking the roasting material at the point where it passes from one tier to the other and at the same time enables the guide or screen to rise in the event of the hollow shaft expanding.

A preferable form of the invention is shown in the acconmanying drawings in which .l igure .1, illustrates an axial longitlulinal section of a roasting 'l'urnace provided with the improved device. Fig. 2 is a cross section of l ig. .l. on the line r\-l3. Fig. 3 illustrates parts of Fig. 1 and the main features of the invention on an enlarged scale and Fi s 4; and show in detail the mode of attaching the screen or guide arrangement to the hollow shaft of the agitating device.

According to this invention beneath each oblique drop opening 0, through which the ore is caused to pass from one grate on to the next, is a guide or screen 7) having the same angular inclination. This guide or screen consists of an oblique plate which is secured to the rotary shaft (3 in a suitable manner as will be hereinafter more fully described. The screen 0 extends down close to the surtace of the next lower stage and in this way acts as a guide for the ore in its passage to the lower stage without: any possibility of dust being stirred up. shown in Figs. It and the screen plates 7; are arranged directly vertically beneath two agitating arms or scrapers Z which rotate in the next higher tier, so that the screens appear always beneath the drop openings at the same moment in which the arms Z in the upper tier sweep the ore into the drop open ings. The arms or, of the tier in which the screen plates are arranged a re secured to the shaft 0 at right; angles with regard to the arms I in the stage tier above.

in order to exclude the current of gases from the or. at the point: of transfer, the upper edge (Z of the screen Z) is caused to 1'0- tate within an annular member or ring 0 located in a ring f of stone, or like material so as to be protected against the adhesion of ore. As will be seen the ring 6 not only excludes the gas current from the roasting material, but it also enables the screen to rise in the event of an expansion of the hollow shaft.

The attachment of the individual screens to the hollow shaft is effected preferably as shown in Figs. i and 5. Each screen carries, by means of an arm g, a suitably curved plate 72, adapted to lit against the shaft 0, and provided with several, say for instance four, lugs i. These lugs can be slipped beneath or into engagement with suitable projections 70 provided on the hollow shaft so that as the screen 1) tends to descend under the influence of gravity it becomes securely fixed on the hollow shaft.

Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed, I declare that what I claim is 1. In a roasting furnace, in combination, a pair of superposed hearths, the upper one of said hearths being provided with an opening, a rotatable vertical shaft extending through said opening, the wall of said opening being inclined downwardly toward said shaft, an agitating arm carried by said shaft above said upper hearth to agitate the material thereon and to cause it to pass through said opening onto the lower hearth, and a guide plate carried by said shaft and positioned below said upper hearth, said plate being inclined to the degree that the wall of said opening is inclined and forming a continuation thereof, said plate being positioned with its ore guiding surface facing said shaft, whereby the ore which passes along said guide from the upper hearth to the lower hearth will be protected from the upwardly flowing gases.

2. In a roasting furnace in combination, a pair of super-posed hearths, the upper one of said hearths being provided with a downwardly inclined drop opening, a rotatable vertical shaft, an agitating arm carried thereby to agitate the material in said upper hearth and a screen plate carried by said shaft beneath said opening and registering thereon, said plate having a surface adapted to guide the material from the upper hearth to the lower hearth, said upper hearth being provided with an annular recess surround ing said opening, said plate having its upper edge projecting into said recess. 7

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

MAURICE VAN MARCKE DE LUllIMEN.

lVitnesses Louis VANBORY, Bnssm F. DUNLAP.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

' Washington, I). 0'. 

